Which of the following is an example of a polygenic trait? A. The flower color of a plant is determined by how three different alleles are paired in the plant. B. A dominant form of a gene determines short ear length in an animal while a recessive form determines long ear length. C. Spotted wings on a species of owl form as the result of two alleles that are both expressed equally. D. Human height is determined by several genes located on different chromosomes.